mysteriendrama/lib/python3.11/site-packages/django/template/loader_tags.py
2023-07-22 12:13:39 +02:00

353 lines
13 KiB
Python

import posixpath
from collections import defaultdict
from django.utils.safestring import mark_safe
from .base import Node, Template, TemplateSyntaxError, TextNode, Variable, token_kwargs
from .library import Library
register = Library()
BLOCK_CONTEXT_KEY = "block_context"
class BlockContext:
def __init__(self):
# Dictionary of FIFO queues.
self.blocks = defaultdict(list)
def __repr__(self):
return f"<{self.__class__.__qualname__}: blocks={self.blocks!r}>"
def add_blocks(self, blocks):
for name, block in blocks.items():
self.blocks[name].insert(0, block)
def pop(self, name):
try:
return self.blocks[name].pop()
except IndexError:
return None
def push(self, name, block):
self.blocks[name].append(block)
def get_block(self, name):
try:
return self.blocks[name][-1]
except IndexError:
return None
class BlockNode(Node):
def __init__(self, name, nodelist, parent=None):
self.name, self.nodelist, self.parent = name, nodelist, parent
def __repr__(self):
return "<Block Node: %s. Contents: %r>" % (self.name, self.nodelist)
def render(self, context):
block_context = context.render_context.get(BLOCK_CONTEXT_KEY)
with context.push():
if block_context is None:
context["block"] = self
result = self.nodelist.render(context)
else:
push = block = block_context.pop(self.name)
if block is None:
block = self
# Create new block so we can store context without thread-safety issues.
block = type(self)(block.name, block.nodelist)
block.context = context
context["block"] = block
result = block.nodelist.render(context)
if push is not None:
block_context.push(self.name, push)
return result
def super(self):
if not hasattr(self, "context"):
raise TemplateSyntaxError(
"'%s' object has no attribute 'context'. Did you use "
"{{ block.super }} in a base template?" % self.__class__.__name__
)
render_context = self.context.render_context
if (
BLOCK_CONTEXT_KEY in render_context
and render_context[BLOCK_CONTEXT_KEY].get_block(self.name) is not None
):
return mark_safe(self.render(self.context))
return ""
class ExtendsNode(Node):
must_be_first = True
context_key = "extends_context"
def __init__(self, nodelist, parent_name, template_dirs=None):
self.nodelist = nodelist
self.parent_name = parent_name
self.template_dirs = template_dirs
self.blocks = {n.name: n for n in nodelist.get_nodes_by_type(BlockNode)}
def __repr__(self):
return "<%s: extends %s>" % (self.__class__.__name__, self.parent_name.token)
def find_template(self, template_name, context):
"""
This is a wrapper around engine.find_template(). A history is kept in
the render_context attribute between successive extends calls and
passed as the skip argument. This enables extends to work recursively
without extending the same template twice.
"""
history = context.render_context.setdefault(
self.context_key,
[self.origin],
)
template, origin = context.template.engine.find_template(
template_name,
skip=history,
)
history.append(origin)
return template
def get_parent(self, context):
parent = self.parent_name.resolve(context)
if not parent:
error_msg = "Invalid template name in 'extends' tag: %r." % parent
if self.parent_name.filters or isinstance(self.parent_name.var, Variable):
error_msg += (
" Got this from the '%s' variable." % self.parent_name.token
)
raise TemplateSyntaxError(error_msg)
if isinstance(parent, Template):
# parent is a django.template.Template
return parent
if isinstance(getattr(parent, "template", None), Template):
# parent is a django.template.backends.django.Template
return parent.template
return self.find_template(parent, context)
def render(self, context):
compiled_parent = self.get_parent(context)
if BLOCK_CONTEXT_KEY not in context.render_context:
context.render_context[BLOCK_CONTEXT_KEY] = BlockContext()
block_context = context.render_context[BLOCK_CONTEXT_KEY]
# Add the block nodes from this node to the block context
block_context.add_blocks(self.blocks)
# If this block's parent doesn't have an extends node it is the root,
# and its block nodes also need to be added to the block context.
for node in compiled_parent.nodelist:
# The ExtendsNode has to be the first non-text node.
if not isinstance(node, TextNode):
if not isinstance(node, ExtendsNode):
blocks = {
n.name: n
for n in compiled_parent.nodelist.get_nodes_by_type(BlockNode)
}
block_context.add_blocks(blocks)
break
# Call Template._render explicitly so the parser context stays
# the same.
with context.render_context.push_state(compiled_parent, isolated_context=False):
return compiled_parent._render(context)
class IncludeNode(Node):
context_key = "__include_context"
def __init__(
self, template, *args, extra_context=None, isolated_context=False, **kwargs
):
self.template = template
self.extra_context = extra_context or {}
self.isolated_context = isolated_context
super().__init__(*args, **kwargs)
def __repr__(self):
return f"<{self.__class__.__qualname__}: template={self.template!r}>"
def render(self, context):
"""
Render the specified template and context. Cache the template object
in render_context to avoid reparsing and loading when used in a for
loop.
"""
template = self.template.resolve(context)
# Does this quack like a Template?
if not callable(getattr(template, "render", None)):
# If not, try the cache and select_template().
template_name = template or ()
if isinstance(template_name, str):
template_name = (
construct_relative_path(
self.origin.template_name,
template_name,
),
)
else:
template_name = tuple(template_name)
cache = context.render_context.dicts[0].setdefault(self, {})
template = cache.get(template_name)
if template is None:
template = context.template.engine.select_template(template_name)
cache[template_name] = template
# Use the base.Template of a backends.django.Template.
elif hasattr(template, "template"):
template = template.template
values = {
name: var.resolve(context) for name, var in self.extra_context.items()
}
if self.isolated_context:
return template.render(context.new(values))
with context.push(**values):
return template.render(context)
@register.tag("block")
def do_block(parser, token):
"""
Define a block that can be overridden by child templates.
"""
# token.split_contents() isn't useful here because this tag doesn't accept
# variable as arguments.
bits = token.contents.split()
if len(bits) != 2:
raise TemplateSyntaxError("'%s' tag takes only one argument" % bits[0])
block_name = bits[1]
# Keep track of the names of BlockNodes found in this template, so we can
# check for duplication.
try:
if block_name in parser.__loaded_blocks:
raise TemplateSyntaxError(
"'%s' tag with name '%s' appears more than once" % (bits[0], block_name)
)
parser.__loaded_blocks.append(block_name)
except AttributeError: # parser.__loaded_blocks isn't a list yet
parser.__loaded_blocks = [block_name]
nodelist = parser.parse(("endblock",))
# This check is kept for backwards-compatibility. See #3100.
endblock = parser.next_token()
acceptable_endblocks = ("endblock", "endblock %s" % block_name)
if endblock.contents not in acceptable_endblocks:
parser.invalid_block_tag(endblock, "endblock", acceptable_endblocks)
return BlockNode(block_name, nodelist)
def construct_relative_path(current_template_name, relative_name):
"""
Convert a relative path (starting with './' or '../') to the full template
name based on the current_template_name.
"""
new_name = relative_name.strip("'\"")
if not new_name.startswith(("./", "../")):
# relative_name is a variable or a literal that doesn't contain a
# relative path.
return relative_name
new_name = posixpath.normpath(
posixpath.join(
posixpath.dirname(current_template_name.lstrip("/")),
new_name,
)
)
if new_name.startswith("../"):
raise TemplateSyntaxError(
"The relative path '%s' points outside the file hierarchy that "
"template '%s' is in." % (relative_name, current_template_name)
)
if current_template_name.lstrip("/") == new_name:
raise TemplateSyntaxError(
"The relative path '%s' was translated to template name '%s', the "
"same template in which the tag appears."
% (relative_name, current_template_name)
)
has_quotes = (
relative_name.startswith(('"', "'")) and relative_name[0] == relative_name[-1]
)
return f'"{new_name}"' if has_quotes else new_name
@register.tag("extends")
def do_extends(parser, token):
"""
Signal that this template extends a parent template.
This tag may be used in two ways: ``{% extends "base" %}`` (with quotes)
uses the literal value "base" as the name of the parent template to extend,
or ``{% extends variable %}`` uses the value of ``variable`` as either the
name of the parent template to extend (if it evaluates to a string) or as
the parent template itself (if it evaluates to a Template object).
"""
bits = token.split_contents()
if len(bits) != 2:
raise TemplateSyntaxError("'%s' takes one argument" % bits[0])
bits[1] = construct_relative_path(parser.origin.template_name, bits[1])
parent_name = parser.compile_filter(bits[1])
nodelist = parser.parse()
if nodelist.get_nodes_by_type(ExtendsNode):
raise TemplateSyntaxError(
"'%s' cannot appear more than once in the same template" % bits[0]
)
return ExtendsNode(nodelist, parent_name)
@register.tag("include")
def do_include(parser, token):
"""
Load a template and render it with the current context. You can pass
additional context using keyword arguments.
Example::
{% include "foo/some_include" %}
{% include "foo/some_include" with bar="BAZZ!" baz="BING!" %}
Use the ``only`` argument to exclude the current context when rendering
the included template::
{% include "foo/some_include" only %}
{% include "foo/some_include" with bar="1" only %}
"""
bits = token.split_contents()
if len(bits) < 2:
raise TemplateSyntaxError(
"%r tag takes at least one argument: the name of the template to "
"be included." % bits[0]
)
options = {}
remaining_bits = bits[2:]
while remaining_bits:
option = remaining_bits.pop(0)
if option in options:
raise TemplateSyntaxError(
"The %r option was specified more than once." % option
)
if option == "with":
value = token_kwargs(remaining_bits, parser, support_legacy=False)
if not value:
raise TemplateSyntaxError(
'"with" in %r tag needs at least one keyword argument.' % bits[0]
)
elif option == "only":
value = True
else:
raise TemplateSyntaxError(
"Unknown argument for %r tag: %r." % (bits[0], option)
)
options[option] = value
isolated_context = options.get("only", False)
namemap = options.get("with", {})
bits[1] = construct_relative_path(parser.origin.template_name, bits[1])
return IncludeNode(
parser.compile_filter(bits[1]),
extra_context=namemap,
isolated_context=isolated_context,
)